Afaik only webtorrent desktop can talk to browsers. https://webtorrent.io/desktop/
Discussion
I've read that other torrent implementations were adding support for websockets, that's why I tried, but
If you go to the "Can WebTorrent clients connect to normal BitTorrent clients?" section, it lists a couple, namely Vuze and TorrentMedia (first I've heard of that one).
Unfortunately, so far bigger clients like Transmission/uTorrent/qBittorrent/Deluge don't seem to have added support for websocket magnets yet.